Can folks just verify that all types of upgrade instruments (GPU, RPU, miles+cash) should be returned/refunded when a ticket with a confirmed upgrade has to be changed before departure?

I know that's supposed to be the case with waitlisted upgrades that don't clear, although I've had more than my share of challenges getting the cash portion of upgrades refunded. However, for the first time I have to change a ticket that has confirmed upgrades (one using RPU, one using miles), and want to make sure I don't just lose the instruments if the ticket is changed. Or if there's some procedure I should call to "undo" the upgrade before making a change to it.

Alternatively, if there is R upgrade space available on the flights I want to change to, is there a painless way to just keep the upgrades in effect while the flights are changed?